|Hi Sindhu - more detail would help:-|
Such as monitor make and model, whether conventional or flat.
With everything powered *OFF*, I would:-
a) first disconnecting and reconnect power and interface cables.
b) try a different monitor - if fault remains, problem is in pc.
c) if for (b) fault disappears, problem is in monitor.
Please advise back on progress.
Good Luck - Keep us posted.